Yes, the case is connected to mains earth, the 0v is connected to the chassis via a CL60 thermistor. Each F5 has its own case and is set up in the same way.
check the mosfets drain tab to mains earth, with a multimeter should show the same resistance, for all, to about 30ohm
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Joined 2002
static discharge will do this 🙂 make sure your heat sinks and chassis is actually grounded properly.
I will recheck the grounding, but that would fit the facts - once the static is discharged then it does not happen again.
Some pics................
Just for s**ts and giggles I thought I'd post these.
Boards are Peter Daniels amp and Cviller PSU, real nice boards. I'm using Toshiba 2SK1530 and 2SJ201 for outputs with no thermal comp. and no overcurrent protection. It did take awhile to set the bias but it is rock solid now. I'm running the voltage across R11/R12 at .640 Vdc and thus the bias at 1.3617 amps.
Anteck transfo and Pers Anders RFB02 boards which I stuffed with MUR3060s and 10nf caps.
The AC wiring is temporary(probably).
The only problem is now that I have it "mocked" up and running it sounds so good that I have no inclination or motivation to put it in a proper chassis.
Just for s**ts and giggles I thought I'd post these.
Boards are Peter Daniels amp and Cviller PSU, real nice boards. I'm using Toshiba 2SK1530 and 2SJ201 for outputs with no thermal comp. and no overcurrent protection. It did take awhile to set the bias but it is rock solid now. I'm running the voltage across R11/R12 at .640 Vdc and thus the bias at 1.3617 amps.
Anteck transfo and Pers Anders RFB02 boards which I stuffed with MUR3060s and 10nf caps.
The AC wiring is temporary(probably).
The only problem is now that I have it "mocked" up and running it sounds so good that I have no inclination or motivation to put it in a proper chassis.
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Yes. I had them on some of his 8.5" X 6" X 1" heatsinks and even at lower bias, .590/1.25amps I couldn't touch them for longer than 4-5 seconds.
With the larger sized heatsinks from him that I'm using now, 10" X 8" X 2", they barely get warm.
Nice, what kind of Silpads are you using under the Toshiba's? They look like a pillow, very thick.
They are aluminum oxide pads with thermal grease. I did not have any sil-pads on hand and these had been laying around getting in my way.
Grounds / mains earth all connected properly; drain to earth measures 17ohms; and today no problems when I touch the cases.
Since it is all working I am going to ignore this feature.
Thanks for your suggestions.
Since it is all working I am going to ignore this feature.
Thanks for your suggestions.
run a continuity test, if the meter pegs or beeps from drain-chassis, you must check and re-seat the fet isolators...
I had checked that but just in case I have moved something I will check again.
Continuity test shows that Gate/Drain are OK, Source bleeps for a fraction of a second and that is that. The results are the same if the FETs are no longer bolted to the heatsinks. However take out the thermistor from star-ground to chassis earth and Source no longer bleeps at all.
Drain to Chassis earth is steady at 40R - with the thermistor in place - without the thermistor there is no connection.
Drain to 0v is 30R.
I can understand the Drain readings based on the circuit - it is the Source readings that I cannot fathom.
I will run without the star-ground to chassis earth tomorrow and see what happens.
Drain to Chassis earth is steady at 40R - with the thermistor in place - without the thermistor there is no connection.
Drain to 0v is 30R.
I can understand the Drain readings based on the circuit - it is the Source readings that I cannot fathom.
I will run without the star-ground to chassis earth tomorrow and see what happens.
At least the parts which are there look pretty.
The problemo i have is with the rack.
Did everyone in the whole D world build that thread rod and nuts thing ?
I'm going to follow the advice in your sig line and just say that I don't know anyone that has built one.
Everyone I know makes alot more money than me.😀
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Joined 2002